Sardines, being so salty and fishy, need something to soften the taste. I find hard-boiled egg to be an excellent accompaniment, with this in mind.

For a very simple open-faced sandwich, ideally on some dark-grain bread, top a layer of sardine filets with slices of hard-boiled egg. Lightly salted and peppered with a little bit of red onion, as a garnish, this is a really nice way to enjoy the fish. This is a really common snack, out here in Estonia.